That depends upon how you are reaching the Internet.

If you use cable or DSL internet, it travels through wires.

If you use 4G, 5G, or WiFi from somewhere outside the walls, it uses radio.

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Wireless internet connections use light in the radio frequency ranges.

If you want to send someone a signal with visible light, you can turn the light on and off to communicate in Morse code. This isn't as time-efficient as using a whole display, but it allows you a lot of flexibility - the receiver can stand anywhere, and the sender can turn the light on and off without worrying whether it is oriented correctly. Computers do something similar. The encoding system is much more complicated than Morse code, but the basic idea of changing how the light is emitted over time to transmit data is the same.

These radio frequency ranges have wavelengths between millimeters and meters (they go longer, but the longer wavelengths usually aren't' used for data channels). For these long wavelengths, many physical barriers are translucent, the way cloudy glass is for visible light. The transition isn't perfect, but we intentionally use an encoding that can handle a little bit of noise so you can still receive those signals.

As for the signal, imagine a clock face with a hand turning very fast, drawing a circle. Divide the clock into 4 sections (like a graph). I'm going to draw a circle around the very center(origin) of the clock. If I want to send a 1, I shall make the signal stronger, and the circle will get bigger. If I to send a 0, my signal gets quieter and lets the circle shrink.

Back to the hand. I have from the time the hand passes 12 to 3 to send a 1 or 0. I send a 1, so my circle in this section is big as the hand passes. My next bit is a 0, so for 3 to 6, my circle curves toward the center. 6 to 9, another 0, so my circle stays in the center. 9 to 12, I want to send a 1, so it curves out. Each time the hand goes around, I send you 4 bits of info, by changing signal strength. (Amplitude modulation... AM)

What if we want to talk faster? Well, I could speed up the hand(clock speed), I could divide the clock into more sections so we get more bits per revolution of the hand, or many other combinations...

But the principal is the same, we agree that some change or other property of the signal means something. We could use a light bulb, a buzzer, flags... So long as we agree on the system. If we use a wire, it is an electric pulse. If we are on wifi, that pulse is from a small radio transmitter. Fiber optic uses light travelling through special cables.

From your laptop to your home router it's WiFi, so radio signals/electromagnetic waves. Those obviously travel through walls. From your home router to the access points of your provider, it's probably copper wires which carry signals as electric current, and from your providers network into the rest of the larger world it's optic fiber lines, transporting data as light pulses.

Your mileage may vary, as your laptop may be connected via (copper) cable to a router, or you may be lucky enough to have to have optic fibre lines directly into your house.

Your mobile internet connection (3/4/5G) also uses electromagnetic waves to reach the next cell tower, which is again connected via optic fibre lines to your providers network.

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